We often get asked if we would consider making a version of our popular improved Jelco tonearm mounting collar with a facility for adjusting vertical tracking angle on the fly (VTAF). VTAF is an alluring idea which appeals to audiophiles keen to extract the last nth of performance from the vinyl rig, but we have some reservations regarding whether this is a feature that genuinely delivers benefits, as opposed to added complication and cost.
Let’s start by looking at the benefit of accurate VTA setting. Actually let’s start by clarifying the terminology – some people get really wound up when someone mentions VTA when they think the correct term is Stylus Rake Angle (SRA). This does not matter, as long as we understand that what is important is that the stylus tip sits in the groove at the correct angle, and that is usually held to be 92 degrees, or slightly forward of vertical. That 92 degrees comes about because the original cutting lathe head is aligned that way for the very practical reason that ‘swarf’ cut from the original lacquer spirals out of the cut groove in away that does not clog the cutting head. Clearly it’s a Good Thing for your replay stylus tip to be aligned in the same way, and good alignment matters increasingly as we look at tip profiles with sharper edges such as extended line contact and micro-ridge types.
How do you know when your stylus tip is correctly aligned in the groove? Some people stick to manufacturers’ recommendations on tracking force and setting the arm tube level – that actually works pretty well with cartridges from the likes of Ortofon which are very consistently made, but often it’s rather more hit and miss. Other people, including Michael Fremer, recommend using a USB microscope to zoom in on the tip when it’s sitting on a reflective surface of roughly LP thickness, to see the actual tip angle, and then adjust if necessary. That’s not a bad idea for setting your starting position, but there are a few things to bear in mind – firstly be aware that the portion of the tip that sits in the groove may not be cut exactly like the visible ‘shank’ of the main part of the tip; also when the stylus is in the groove of a moving record drag will tend to cause the cartridge suspension to be slightly compressed in comparison to the static situation, so the tip angle will change, and note that drag also depends on how modulated the grooves are, so a bit of a moving target. Furthermore, we cannot be totally certain that the original cutter head was set at 92 degrees, and of course the tip angle will vary a touch depending on the thickness of the LP being played. So, quite a bit of uncertainty going on here, but the USB microscope method is good for showing up gross tip alignment issues and helping you to get more or less where you need to be with your VTA setup.
Whichever method you choose to set the tonearm height, and therefore VTA, in roughly the right position to start with, you need to listen to some actual music and carry out some arm height adjustments to listen for the point at which the music sounds ‘right’, which can mean the soundstage snaps into focus, instruments become clearer and the ‘ambience’ of the recording sounds natural. You should do this when the ambient temperature is nice and warm , eg 20-24C so the cartridge suspension is working as the maker intended. The idea that you can carry out these adjustments while the record is playing is certainly enticing, but in our experience even gross adjustments of arm height result in quite subtle sound changes and rapid twiddling of a VTA knob does not guarantee that you’ll home in on the best setting any easier than simply adjusting arm height in increments, then sitting down and listening to the music to evaluate each adjustment. You do need to sit down and let the music speak to you for a while (as with any system changes).
For Jelco and Jelco-derived arms, our improved mounting collars provide greatly enhanced support of the arm’s pillar, but also a nice smooth vertical adjustment facility. It is very easy to adjust the arm up or down by 5mm or so (not while the record is playing, of course) until you home in on the best sound for a particular cartridge, then tweak by finer degrees until VTA is spot-on. In practice this is just as quick as with a tonearm that has a VTAF adjustment facility. Our tip for recording the optimum VTA for future reference is to place a small circular bubble level on the headshell, without altering the VTF, and then make a note of the bubble position – you can then quickly replicate that position in future.
There are some practical reasons why we have chosen not to develop a VTAF collar for Jelco tonearms. Firstly, the cost of doing so in a way that does not mean poorer support of the arm and therefore degraded sound quality is considerable. A properly designed VTAF Jelco collar that fits within any turntable’s arm board or recess and within a close-able dust cover would not be an inexpensive option. Secondly, a VTAF mechanism invariably means that the collar height is increased by some margin, and that sometimes means it’s then impossible to set the arm low enough to achieve correct VTA under any circumstances, so actually a self-defeating objective. These two reasons explain why we feel that VTAF is not necessarily a good thing, and with Jelco arms rather difficult and expensive to implement in an intelligent manner.
We hope that’s helpful